Fix swift package init --help printout (#3407)

* Fix --help printout

* What a fixed --help would look like

All of our subcommands need fixing. This is a demo of what fixing all the commands would look like

Also includes some fillings for `Options()` that didn't have any help

* Testable import, and throw InternalError

* Updated all remaining commands

* Bump Swift-Argument-Parser

Includes the new constructor that we need

* Reverted import of Commands

* Reverted indexStore, to be implemented in separate pr

Co-authored-by: Miguel Perez <[email protected]>
(cherry picked from commit a52d4d8)

Author: miggs597